The actual dimensions don’t matter as much as how many people fit comfortably.
Open bench seating will fit more people in a hot tub due to the lack of sculpted contours separating each user. I call it “negotiable seating”, where you can scooch over to make more room to pack in as many people as possible.
Compare that to a more aggressively-sculpted hot tub with each person in their own “pod”, where they may need to stand up to relocate.
Sculpted vs open bench seating
Also, some hot tubs have a wider shelf around the perimeter, providing ample shelf space for cups and more comfortable sill-sitting, but this results in less interior space.
Narrow vs wide sill perimeter
Also, keep in mind that people also have legs, not just butts. A six-seater hot tub may have enough seats for six butts, but not enough room for twelve legs.
Large vs small foot well
Hot Tubs Galore
19238 96 Avenue, Unit 111
Surrey, BC V4N 4C1
Behind the Tim Hortons